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在 Flutter 项目中实现 iOS 实时活动

我们将为一个 Flutter 项目创建一个带有秒表实现的实时活动 (Live Activity)。该项目将包括 Flutter 端的实现以及 Xcode 项目中的原生实现。

Flutter 端实现

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我们将创建一个类，该类将实现三个方法：

  • startLiveActivity()
  • updateLiveActivity()
  • stopLiveActivity()
class DynamicIslandManager {
  final String channelKey;
  late final MethodChannel _methodChannel;


  DynamicIslandManager({required this.channelKey}) {
    _methodChannel = MethodChannel(channelKey);
  }


  Future<void> startLiveActivity({required Map<String, dynamic> jsonData}) async {
    try {
      await _methodChannel.invokeListMethod('startLiveActivity', jsonData);
    } catch (e, st) {
      log(e.toString(), stackTrace: st);
    }
  }


  Future<void> updateLiveActivity(
      {required Map<String, dynamic> jsonData}) async {
    try {
      await _methodChannel.invokeListMethod('updateLiveActivity', jsonData);
    } catch (e, st) {
      log(e.toString(), stackTrace: st);
    }
  }


  Future<void> stopLiveActivity() async {
    try {
      await _methodChannel.invokeListMethod('stopLiveActivity');
    } catch (e, st) {
      log(e.toString(), stackTrace: st);
    }
  }
}

我们将构建一个秒表应用，为了将秒表计时器数据传递给原生方法，我们需要创建一个数据模型，并以类似 JSON 的 map 格式将其发送到方法通道调用中。

class DynamicIslandStopwatchDataModel {
  final int elapsedSeconds;


  DynamicIslandStopwatchDataModel({
    required this.elapsedSeconds,
  });


  Map<String, dynamic> toMap() {
    return <String, dynamic>{
      'elapsedSeconds': elapsedSeconds,
    };
  }
}

每个方法都将包含调用相应原生方法的必要代码。

这是在 Flutter 端运行它所需的初始设置。在此之后，我们实现了一个带有必要方法调用的基本秒表应用 UI。

class _StopWatchScreenState extends State<StopWatchScreen> {
  int seconds = 0;
  bool isRunning = false;
  Timer? timer;


  /// channel key is used to send data from flutter to swift side over
  /// a unique bridge (link between flutter & swift)
  final DynamicIslandManager diManager = DynamicIslandManager(channelKey: 'PW');


  void startTimer() {
    setState(() {
      isRunning = true;
    });


    // invoking startLiveActivity Method
    diManager.startLiveActivity(
      jsonData: DynamicIslandStopwatchDataModel(elapsedSeconds: 0).toMap(),
    );


    timer = Timer.periodic(const Duration(seconds: 1), (timer) {
      setState(() {
        seconds++;
      });
            // invoking the updateLiveActivity Method
      diManager.updateLiveActivity(
        jsonData: DynamicIslandStopwatchDataModel(
          elapsedSeconds: seconds,
        ).toMap(),
      );
    });
  }


  void stopTimer() {
    timer?.cancel();
    setState(() {
      seconds = 0;
      isRunning = false;
    });


    // invoking the stopLiveActivity Method
    diManager.stopLiveActivity();
  }


  @override
  void dispose() {
    timer?.cancel();
    super.dispose();
  }


  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(
        title: const Text('Stopwatch App'),
      ),
      body: Center(
        child: Column(
          mainAxisAlignment: MainAxisAlignment.center,
          children: <Widget>[
            Text(
              'Stopwatch: $seconds seconds',
              style: const TextStyle(fontSize: 24),
            ),
            const SizedBox(height: 20),
            Row(
              mainAxisAlignment: MainAxisAlignment.center,
              children: <Widget>[
                ElevatedButton(
                  onPressed: isRunning ? null : startTimer,
                  child: const Text('Start'),
                ),
                const SizedBox(width: 20),
                ElevatedButton(
                  onPressed: isRunning ? stopTimer : null,
                  child: const Text('Stop'),
                ),
              ],
            ),
          ],
        ),
      ),
    );
  }
}

原生端实现

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Xcode 项目配置

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  1. 在 Xcode 中打开您的项目，并在 “General” 选项卡中将最低部署版本设置为 iOS 16.1。
Xcode “General” 选项卡，显示最低部署版本设置为 iOS 16.1
  1. 在 Info.plist 中添加一个新键 NSSupportsLiveActivities 并将其值设置为 YES (布尔值)。

Info.plist

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<key>NSSupportsLiveActivities</key>
<true/>
  1. 从操作栏中选择 File > New > Target，搜索 WidgetExtension 并创建一个新的 widget。

代码端实现

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让我们创建一个名为 LiveActivityManager 的类来管理我们的灵动岛 (Dynamic Island) 的实时活动。这个类将包含三个方法：startLiveActivity()、updateLiveActivity() 和 stopLiveActivity()。

Swift

import ActivityKit
import Flutter
import Foundation


@available(iOS 16.1, *)
class LiveActivityManager {


    private var stopwatchActivity: Activity<StopwatchWidgetAttributes>? = nil


    func startLiveActivity(data: [String: Any]?, result: FlutterResult) {
        let attributes = StopwatchWidgetAttributes()


        if let info = data {
            let state = StopwatchWidgetAttributes.ContentState(
                elapsedTime: info["elapsedSeconds"] as? Int ?? 0
            )
            stopwatchActivity = try? Activity<StopwatchWidgetAttributes>.request(
                attributes: attributes, contentState: state, pushType: nil)
        } else {
            result(FlutterError(code: "418", message: "Live activity didn't invoked", details: nil))
        }
    }


    func updateLiveActivity(data: [String: Any]?, result: FlutterResult) {
        if let info = data {
            let updatedState = StopwatchWidgetAttributes.ContentState(
                elapsedTime: info["elapsedSeconds"] as? Int ?? 0
            )


            Task {
                await stopwatchActivity?.update(using: updatedState)
            }
        } else {
            result(FlutterError(code: "418", message: "Live activity didn't updated", details: nil))
        }
    }


    func stopLiveActivity(result: FlutterResult) {
        do {
            Task {
                await stopwatchActivity?.end(using: nil, dismissalPolicy: .immediate)
            }
        } catch {
            result(FlutterError(code: "418", message: error.localizedDescription, details: nil))
        }
    }
}

每个方法都有其特定的功能。startLiveActivity() (顾名思义) 负责启动实时活动，从而触发灵动岛的功能。同样，stopLiveActivity() 和 updateLiveActivity() 分别处理停止实时活动和更新灵动岛上显示的数据。

接下来，打开 StopWatchDIWidgetLiveActivity.swift 并修改 StopwatchDIWidgetAttributes 结构体 (如代码片段所示)。这个属性结构体作为数据模型，用于保存要在 UI 上显示的信息 (直接来自 Flutter)，并且还可以根据需要修改 UI。

Swift

struct StopwatchWidgetAttributes: ActivityAttributes {
    public typealias stopwatchStatus = ContentState


    public struct ContentState: Codable, Hashable {
        var elapsedTime: Int
    }
}

现在，只剩下灵动岛的 UI 了！(太棒了，我们已经走到这一步了！) 整个灵动岛的 UI 都需要使用 SwiftUI 来创建。在本文中，我们设计了一个简单的 UI (但您可以根据需要随意自定义)。

这段 UI 代码应该写在 StopwatchWidgetLiveActivity 结构体内部。删除结构体中现有的代码，然后可以参考下面的代码：

SwiftUI

struct StopwatchWidgetLiveActivity: Widget {


    func getTimeString(_ seconds: Int) -> String {
        let hours = seconds / 3600
        let minutes = (seconds % 3600) / 60
        let seconds = (seconds % 3600) % 60


        return hours == 0 ?
                String(format: "%02d:%02d", minutes, seconds)
                : String(format: "%02d:%02d:%02d", hours, minutes, seconds)
    }


    var body: some WidgetConfiguration {
        ActivityConfiguration(for: StopwatchWidgetAttributes.self) { context in
            HStack {
                Text("Time ellapsed")
                    .font(.system(size: 20, weight: .semibold))
                    .foregroundColor(.white)
                Spacer()
                Image(systemName: "timer")
                    .foregroundColor(.white)
                Spacer().frame(width: 10)
                Text(getTimeString(context.state.elapsedTime))
                    .font(.system(size: 24, weight: .semibold))
                    .foregroundColor(.yellow)
            }
            .padding(.horizontal)
            .activityBackgroundTint(Color.black.opacity(0.5))


        }
        dynamicIsland: { context in
            DynamicIsland {
                DynamicIslandExpandedRegion(.center) {
                    VStack(alignment: .center) {
                        Text("Pushwoosh Timer")
                        Spacer().frame(height: 24)
                        HStack {
                            Text("Time ellapsed")
                                .font(.system(size: 20, weight: .semibold))
                                .foregroundColor(.white)
                            Spacer()
                            Image(systemName: "timer")
                            Spacer().frame(width: 10)
                            Text(getTimeString(context.state.elapsedTime))
                                .font(.system(size: 24, weight: .semibold))
                                .foregroundColor(.yellow)
                        }.padding(.horizontal)
                    }
                }
            } compactLeading: {
                Image(systemName: "timer").padding(.leading, 4)
            } compactTrailing: {
                Text(getTimeString(context.state.elapsedTime)).foregroundColor(.yellow)
                    .padding(.trailing, 4)
            } minimal: {
                Image(systemName: "timer")
                    .foregroundColor(.yellow)
                    .padding(.all, 4)
            }
            .widgetURL(URL(string: "http://www.pushwoosh.com"))
            .keylineTint(Color.red)
        }
    }
}

别忘了也要修改 AppDelegate 的代码。

AppDelegate.swift

import UIKit
import Flutter


@main
@objc class AppDelegate: FlutterAppDelegate {


    private let liveActivityManager: LiveActivityManager = LiveActivityManager()


    override func application(
        _ application: UIApplication,
        didFinishLaunchingWithOptions launchOptions: [UIApplication.LaunchOptionsKey: Any]?
    ) -> Bool {


        GeneratedPluginRegistrant.register(with: self)


        let controller : FlutterViewController = window?.rootViewController as! FlutterViewController
        let diChannel =  FlutterMethodChannel(name: "PW", binaryMessenger: controller.binaryMessenger)


        diChannel.setMethodCallHandler({ [weak self] (
            call: FlutterMethodCall, result: @escaping FlutterResult) -> Void in
            switch call.method {
            case "startLiveActivity":
                self?.liveActivityManager.startLiveActivity(
                    data: call.arguments as? Dictionary<String,Any>,
                    result: result)
                break


            case "updateLiveActivity":
                self?.liveActivityManager.updateLiveActivity(
                    data: call.arguments as? Dictionary<String,Any>,
                    result: result)
                break


            case "stopLiveActivity":
                self?.liveActivityManager.stopLiveActivity(result: result)
                break


            default:
                result(FlutterMethodNotImplemented)
            }
        })


        return super.application(application, didFinishLaunchingWithOptions: launchOptions)
    }
}

就是这样！这涵盖了实现灵动岛并将其链接到 Flutter 代码所需的一切！

Pushwoosh 代码实现

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Pushwoosh Flutter 插件提供了两种在项目中管理实时活动的方法。

  /// Default setup Live Activity
  Future<void> defaultSetup() async {
    await _channel.invokeMethod("defaultSetup");
  }


  /// Default start Live Activity
  /// [activityId] activity ID
  /// [attributes] attributes
  /// [content] content
  Future<void> defaultStart(String activityId, Map<String, dynamic> attributes, Map<String, dynamic> content) async {
    await _channel.invokeMethod("defaultStart", {"activityId": activityId, "attributes": attributes, "content": content});
  }

defaultSetup() 方法允许您在 Pushwoosh 端管理实时活动的结构和令牌。

在应用程序初始化期间调用此方法。

  Pushwoosh.initialize({"app_id": "XXXXX-XXXXX", "sender_id": "XXXXXXXXXXXX"});
/**
* Call this method `defaultSetup()`
*/
  Pushwoosh.getInstance.defaultSetup();

在应用初始化期间，Pushwoosh 会将您的 push-to-start 令牌发送到服务器，这之后将允许您通过 API 调用来启动实时活动。 要启动实时活动，您需要发出一个 API 请求。以下是请求的示例：

{
  "request": {
    "application": "XXXXX-XXXXX",
    "auth": "YOUR_AUTH_API_TOKEN",
    "notifications": [
      {
        "content": "Message",
        "title":"Title",
        "live_activity": {
          "event": "start", // `start` event
            "content-state": {
                "data": { // You need to pass the parameters in a dictionary with the key data.
                    "emoji": "dynamic data"
                }
            },
           "attributes-type": "DefaultLiveActivityAttributes",
            "attributes": {
                "data": {
                    "name": "static data"
                }
        }
        },
        "devices": [ "XXXXXXXX-XXXX-XXXX-XXXX-XXXXXXXXXXXX" // HWID
       ],
        "live_activity_id": "your_activity_id"
      }
    ]
  }
}

关于 API 的更详细文档

如果您想从您的应用中启动一个简单的实时活动，您可以在 Flutter 中使用以下方法：defaultStart(String activityId, Map<String, dynamic> attributes, Map<String, dynamic> content)

此方法可以在任何触发实时活动启动的事件上调用。

// Function to start Live Activity
  void startLiveActivity() {
    // Create your activity ID
    String activityId = "stopwatch_activity";


    // Define the attributes you want to send to the Live Activity
    Map<String, dynamic> attributes = {
      'title': 'Stopwatch Activity',
      'description': 'This is a live activity for a stopwatch.'
    };


    // Define the content state to update on the Dynamic Island
    Map<String, dynamic> content = {
      'elapsedSeconds': 0
    };


    // Call Pushwoosh's defaultStart method to trigger the Live Activity
    Pushwoosh.getInstance().defaultStart(activityId, attributes, content);
  }